The objective of this study was to analyze the biomechanical effect of an implanted ACL graft by determining the tunnel position according to the aspect ratio (ASR) of the distal femur during flexion-extension motion. To analyze biomechanical characteristics according to the ASR of the knee joint, only male samples were selected to exclude the effects of gender and 89 samples were selected for measurement. The mean age was 50.73 years, and the mean height was 165.22 cm. We analyzed tunnel length, graft bending angle, and stress of the graft according to tunnel entry position and aspect ratio (ratio of antero-posterior depth to medio-lateral width) of the articular surface for the distal femur during single-bundle outside-in anterior cruciate ligament reconstruction surgery. We performed multi-flexible-body dynamic analyses with wherein four ASR (98, 105, 111, and 117%) knee models. The various ASRs were associated with approximately 1-mm changes in tunnel length. The graft bending angle increased when the entry point was far from the lateral epicondyle and was larger when the ASR was smaller. The graft was at maximum stress, 117% ASR, when the tunnel entry point was near the lateral epicondyle. The maximum stress value at a 5-mm distance from the lateral epicondyle was 3.5 times higher than the 15-mm entry position and, the cases set to 111% and 105% ASR, showed 1.9 times higher stress values when at a 5-mm distance compared with a 15-mm distance. In the case set at 98% ASR, the low-stress value showed a without-distance difference from the lateral epicondyle. Our results suggest that there is no relationship between the ASR and femoral tunnel length, A smaller ASR causes a higher graft bending angle, and a larger ASR causes greater stress in the graft

Anatomical descriptions of the lateral retinaculum have been published, but the attachments, name or even existence of its tissue bands and layers are ill-defined. We have examined 35 specimens of the knee. The deep fascia is the most superficial layer and the joint capsule is the deepest. The intermediate layer is the most substantial and consists of derivatives of the iliotibial band and the quadriceps aponeurosis. The longitudinal fibres of the iliotibial band merge with those of the quadriceps aponeurosis adjacent to the patella. These longitudinal fibres are reinforced by superficial arciform fibres and on the deep aspect by transverse fibres of the iliotibial band. The latter are dense and provide attachment of the iliotibial band to the patella and the tendon of vastus lateralis obliquus.

Our study identifies two important new findings which are a constant connection of the deep fascia to the quadriceps tendon superior and lateral to the patella, and, a connection of the deeper transverse fibres to the tendon of vastus lateralis obliquus.